1

MeSH & Principles of Classification

April 13, 2005

2

Medical Subject Headings (MeSH) Thesaurus developed in the 1960s

for online use More detailed than LCSH for

medical terminology Pre-coordinated but not to same

extent as LCSH

3

Vocabulary Same vocabulary is used for

cataloging books and for indexing journals

19,000 main subject headings 82 topical subheadings or qualifiers Each subject heading and qualifier

has a scope note and the categories under which it may be used

4

Vocabulary (cont.) Does not include form, geographic

or language subheadings Does use publication types as

headings Kinds of study, types of study, and

sources of support are specified (“check tags”)

Can limit searching by language, type, medium, location, etc.

5

Descriptors for:Cutaneous adverse events in renal transplant recipients receiving sirolimus-based therapy (journal article)

Adult Aged

Cross-sectional studies Edema/etiology Female Hair/pathology Humans Immunosuppressive

agents/*adverse effects

*Kidney transplantation

Male Middle aged Mucous

membrane/pathology Nails/pathology Sebaceous

glands/pathology Sirolimus/*adverse

effects Skin

diseases/*chemically induced

Skin diseases, Infectious/etiology

6

Syntax Some subject headings are inverted Subject headings may be subdivided,

but no more than two elements are permitted If more than one qualifier is needed,

then the subject heading is repeated. Example:Coronary disease / ep [Epidemiology]Coronary disease / me [Metabolism]*Coronary disease / pc [Prevention & Control]

7

MeSH Thesaurus Available in three forms online

and/or in print: Tree structure Alphabetic list Annotated Alphabetic List

PubMed

8

Alphabetic List 1st section:

every subject heading and subdivision in one alphabetical list regardless of hierarchy

notational equivalent(s) History of the term, including year of

adoption, earlier terms Cross-references

9

Alphabetic List (cont.) 2nd section:

Categories and subcategories Records subcategories in alphabetical

order with their notations

10

Annotated Alphabetic List Only in print form Designed for catalogers, indexers,

and online searchers Contains scope notes, check tags,

and other information not included in the Alphabetic List

11

Principles of Classification Definitions Uses of classification Components of classification

systems “Characteristic of division” Enumerative vs. synthetic schemes

12

Definitions Classification: The systematic

arrangement of objects or concepts in groups or classes according to their similarities and differences or their relation to a set of criteria. (Olson & Boll, 2001)

In bibliographic classification, like subjects are grouped together and related subjects are near one another

13

Definitions (cont.) Class numbers or classification

numbers -- symbols used to identify classes (preferably called notation since they can be alphabetic or alphanumeric)

14

Classification scheme characteristics Dynamic Book numbers (a.k.a. Cutter

numbers) allow for subarrangement of books within a class

Principles of subarrangement within classes achieved with shelflisting

15

Uses of Classification Arrangement of materials on

shelves Arrangement of document

surrogates in paper catalogs Online manipulation of document

surrogates (online shelf list) for online browsing

16

Importance of Browsing Ranganathan’s principle: Save the time of the

user In open stack libraries, browsing is a significant

method of resource discovery In OPACs which include remote resources, the

ability of users to browse an online shelflist increases the likelihood of discovering those remote resources. There is no other way at present to browse remote resources.

The library’s efforts to fully classify a collection results in time savings for users and staff.

17

Components of a Classification Scheme verbal description of things and concepts arrangement into a classed/logical order

that is meaningful and convenient notation alongside each verbal

description; together these form schedules

references to guide user to other aspects of topics or related topics

18

Components of a Classification Scheme (cont.) alphabetical index of terms used in

the schedules with synonyms instructions for use mechanisms for revision

19

Characteristic of division Groups of abstract concepts,

objects, or activities are divided into smaller groups

The criterion for division is called the “characteristic of division”

20

Types of Characteristics of Division (cont.) Genus to species (or group to

member)Primates to Apes

Whole to partsNervous system to Spinal cord

Continuous processTextiles, Carding, Spinning, Weaving, Finishing

21

Types of Characteristics of Division (cont.) Increasing complexity

Music for duets, for trios, for quartets

Chronological (history of a country)Czechoslovakia, 1918-1939, 1939-1945,

1945-1968 Spatial: Continent to Country

Europe to Czech Republic

22

Characteristics of Division (cont.) Division continues until no other

divisions can be made Creates a hierarchy Overlapping hierarchies may exist

as there may be more than one way of dividing a topic

23

Enumerative Classification Schemes Every topic that can be classified is

enumerated in the scheme Topics not enumerated separately

must be classed with a broader topic

Narrow compound topics can be accomodated by narrowing the class

24

Linearity Linearity: documents can only be

shelved by one characteristic Only major aspects of a work are

considered in classification Compound topics present a

problem

25

Solutions to compound topics Rules:

Classify by emphasis of the work Classify by one criterion when two

apply Classify by the first class in the

schedules These rules can be arbitrary and

are of no use to browsers

26

Synthetic Classification Combine notations for different

concepts to create compound notations Faceted classification is one type of

synthetic classification Ranganathan’s colon classification –

five facets Read more about it in Chapter 7, SAOC!